|Número de publicación||US7260991 B2|
|Tipo de publicación||Concesión|
|Número de solicitud||US 10/513,907|
|Número de PCT||PCT/DE2003/000590|
|Fecha de publicación||28 Ago 2007|
|Fecha de presentación||25 Feb 2003|
|Fecha de prioridad||24 Ago 2002|
|También publicado como||DE10238893A1, EP1535027A1, EP1535027B1, US20050223800, WO2004020947A1|
|Número de publicación||10513907, 513907, PCT/2003/590, PCT/DE/2003/000590, PCT/DE/2003/00590, PCT/DE/3/000590, PCT/DE/3/00590, PCT/DE2003/000590, PCT/DE2003/00590, PCT/DE2003000590, PCT/DE200300590, PCT/DE3/000590, PCT/DE3/00590, PCT/DE3000590, PCT/DE300590, US 7260991 B2, US 7260991B2, US-B2-7260991, US7260991 B2, US7260991B2|
|Inventores||Dieter Maurer, Joerg Hauer|
|Cesionario original||Robert Bosch Gmbh|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (6), Citada por (12), Clasificaciones (9), Eventos legales (3)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
The present invention relates to a rotation-rate sensor.
A rotation-rate sensor is discussed in German patent document no. 199 45 859. This rotation-rate sensor, however, has a relatively low working frequency.
In the case of the rotation-rate sensor having a rotary oscillator produced using surface micromechanics, the rotary oscillator or the centrifugal mass is mechanically centrally connected to the substrate via an X-shaped spring at one point. A working frequency is established based on the X-shaped spring and the mass of the rotary oscillator. To increase the working frequency with respect to the rotation-rate sensor from the related art, the spring arms of the X-shaped spring would either need to be widened or shortened. Naturally, a combination of the two measures is also conceivable.
However, these measures may result in the problem that the oscillation amplitude would be decreased and the stretching of the spring material would be increased. The decrease in the oscillation amplitude disadvantageously decreases the sensor sensitivity. The increase in the stretching of the X-shaped spring material may result in the spring material breaking. In addition, the non-linearity of the spring stiffness increases over the deflection if the spring length is shortened while the oscillation amplitude remains constant.
For stable sensor operation, the non-linearity is to be kept as minimal as possible since there is otherwise the risk of non-linear collapse (two stable working points).
In contrast, the rotation-rate sensor of the present invention is believed to have the advantage that the disadvantages of the related art resulting from the measures for increasing the oscillation frequency are prevented.
The spiral spring device of the rotation-rate sensor of the present invention has significantly lower, maximum stretching at the connection for a given deflection. The maximum stretching may also be selected via the size of the radius at the connection. In this context, a large radius signifies minimal stretching at the connection.
It may be particularly advantageous that the spiral spring device is connected to the centrifugal mass such that radial length equalization is achievable. To achieve radial length equalization, it is provided in particular for the spiral spring device to have a bent region at its connection to the centrifugal mass. As a result, the angled end pieces or the bent region may absorb the longitudinal force in the spiral spring devices when rotating the sensor in a plane. If this longitudinal force in the spiral spring device is not reduced, the stiffness increases as a function of the deflection resulting in the non-linearity of the spring stiffness being too great.
The exemplary embodiment and/or exemplary method of the present invention prevents this which is why the radial length equalization also results in a reduction in the non-linearity of the spring stiffness. It is also advantageous for two spiral spring devices to be provided along their greatest extension next to one another in mirror symmetry and together to form one spiral spring. This ensures that a spiral spring for deflections in different directions has a symmetrical characteristic based on its neutral position. For example, the deflection and restoring force during a rotation of the centrifugal mass at an angle about the Z axis in a positive and negative direction are equal. It is also advantageous that two spiral springs are positioned in a V shape such that the legs expand at an opening angle in the direction of the centrifugal mass. Changing the opening angle between the spiral springs allows the detection resonance frequency of the sensor, i.e., the rotation of the centrifugal mass from the substrate level about the X and Y axis to be set.
The relationship of the natural frequencies to one another largely determines the sensor properties, such as sensitivity, immunity to interference, and temperature stability. As a result, via the opening angle of the spiral springs the natural frequencies may be provided so that they are adjustable in a simple, precise, and independent manner. It is also advantageous that a total of four spiral springs are positioned such that they essentially form an X shape. This creates a symmetrical spiral spring shape. It is also advantageous that the opening angle is selected such that the natural frequency is less about the axis of rotation lying perpendicular to the substrate surface than each natural frequency about an axis of rotation lying parallel to the substrate surface. This results in an extraordinarily positive sensing performance. It may also be advantageous that the rotation-rate sensor of the present invention is produced using surface micromechanics or other micromechanic technology.
The use of surface micromechanics for producing the micromechanic rotation-rate sensor of the present invention, in particular a mass production process using a thick EP poly layer with a typical thickness of 10 μm, allows the formation of a stiff sensor structure which enables minimal cross sensitivity. It is additionally advantageous that the anchoring device is fixedly connected to the substrate or that the anchoring device is positioned to be movable relative to the substrate. This renders allows for different applications of the rotation-rate sensor of the present invention. Moreover, it may be advantageous that one or more supporting springs are provided in addition to the spiral springs forming an X shape. This may be advantageously provided according to the exemplary embodiment and/or exemplary method of the present invention to influence other natural frequencies of the sensor in a targeted manner in another embodiment of the sensor.
The exemplary embodiment and/or exemplary method of the present invention provides for a sensor having a greater working frequency, e.g. greater than 5 kHz. In this context, the structure of centrifugal mass 10 is to remain largely unchanged. For a sensor according to the related art, X-shaped bending legs 30-33 would have to be shortened and/or widened for this purpose. This results in a number of problems. These measures of shortening and/or widening spiral spring legs 30-33 would reduce the sensitivity of the sensor. This is not desirable since sensors having high sensitivity are generally desired. In addition, in the case of a wider spring the stretching at the connection of the X spring, as shown in
According to the exemplary embodiment and/or exemplary method of the present invention, spiral spring devices 301-308 are positioned in particular such that first spiral spring device 301 and second spiral spring device 202 are positioned symmetrically, specifically in mirror symmetry, along an axis not shown in
As previously described, the exemplary embodiment and/or exemplary method of the present invention provides for centrifugal mass 10 to be provided in a ring shape in particular which is centered around a center 400. In this context, substrate 100 forms a main substrate level on which centrifugal mass 100 mainly extends. The two directions X and Y shown in the right portion of
According to the exemplary embodiment and/or exemplary method of the present invention, the bent region in first spiral spring device 301 at second end 320 of first spiral spring device 301 and bend 331 at first end 330 of first spiral spring device 301 are provided in the XY plane in particular, i.e., in the main substrate level, in the same direction of axis of affinity 364. This results in a U shape of spiral spring devices 301-308. The exemplary embodiment and/or exemplary method of the present invention provides for the length of first spiral spring device 301 designated by reference numeral 365 in
A suspension point of a spiral spring device 301-308 at anchoring device 200 is not necessarily required to be connected to substrate 100. Spiral spring device 301-308 may also be located between two masses moving relative to one another, for example.
In addition to the X-shaped configuration of spiral springs 360-363 described in
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|Clasificación de EE.UU.||73/535, 73/504.18, 73/504.08, 73/504.12|
|Clasificación internacional||G01C19/56, G01P3/16, G01P15/02|
|8 Nov 2004||AS||Assignment|
Owner name: ROBERT BOSCH GMBH, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MAURER, DIETER;HAUER, JOERG;REEL/FRAME:016551/0534;SIGNING DATES FROM 20041008 TO 20041025
|21 Feb 2011||FPAY||Fee payment|
Year of fee payment: 4
|23 Feb 2015||FPAY||Fee payment|
Year of fee payment: 8